This invention concerns the manufacture of petroleum sulfonates which can particularly be used to confer micellar properties to mixtures of hydrocarbons with water. These products have found a particular use in the manufacture of microemulsions which can be used in the assisted oil recovery.
The petroleum sulfonates are surfactive agents obtained by sulfonation of crude oils or oil fractions obtained by distillation.
The oil bases which can be used according to the process of the invention may be vacuum distillation cuts, particularly those used in the production of lubricating oils, or optionally dewaxed deasphalted distillation residues, for example, a heavy oil known as Bright Stock.
U.S. Pat. No. 3,254,714 discloses the use of microemulsions comprising a petroleum sulfonate for recovering crude oil from underground formations.
U.S. Pat. No. 3,497,006 discloses the use of water-in-oil micellar dispersions having a high water content, i.e. 55 to 90%, to recover the crude oil, the micellar dispersion consisting of a petroleum sulfonate having an average molecular weight of about 350 to 520.
U.S. Pat. No. 3,506,071 discloses the recovery of oil by injecting micellar dispersions whose dispersion phase is water, which preferably consist of a petroleum sulfonate having an average molecular weight of 350 to 520.
U.S. Pat. No. 3,302,713 discloses the injection of an aqueous solution comprising a petroleum sulfonate having an average molecular weight of 450 to 500, which is obtained by sulfonating a hydrocarbon having a boiling range of 371.degree. to 593.degree. C. with gaseous SO.sub.3.
U.S. Pat. No. 3,373,808 discloses the injection of water containing sulfonates obtained by sulfonating a hydrocarbon having a boiling range of 260.degree. to 816.degree. C. and an average molecular weight of 250 to 700 with gaseous or liquid SO.sub.3 ; it is specified that polysulfonation results from raising the reaction temperature and increasing the molar ratio of the sulfonation agent.
U.S. Pat. No. 3,956,372 discloses the manufacture of petroleum sulfonates by sulfonation of a hydrocarbon raw material consisting of gas oil having an average molecular weight of 250 to 700 and containing at least 20% of aromatic constituents with a solution of SO.sub.3 in 1,2-dichlorethane.